Low-Temperature Growth of Two-Dimensional Layered Chalcogenide Crystals on Liquid

The growth of high-quality two-dimensional (2D) layered chalcogenide crystals is highly important for practical applications in future electronics, optoelectronics, and photonics. Current route for the synthesis of 2D chalcogenide crystals by vapor deposition method mainly involves an energy intensive high-temperature growth process on solid substrates, often suffering from inhomogeneous nucleation density and grain size distribution. Here, we first demonstrate a facile vapor-phase synthesis of large-area high-quality 2D layered chalcogenide crystals on liquid metal surface with relatively low surface energy at a growth temperature as low as ∼100 °C. Uniform and large-domain-sized 2D crystals of GaSe and GaxIn1-xSe were grown on liquid metal surface even supported on a polyimide film. As-grown 2D GaSe crystals have been fabricated to flexible photodetectors, showing high photoresponse and excellent flexibility. Our strategy of energy-sustainable low-temperature growth on liquid metal surface may open a route to the synthesis of high-quality 2D crystals of Ga-, In-, Bi-, Hg-, Pb-, or Sn-based chalcogenides and halides.

Association Analysis of Myosin Heavy-chain Genes mRNA Transcription with the Corresponding Proteins Expression of Longissimus Muscle in Growing Pigs

The goal of this work was to investigate the correlations between MyHC mRNA transcription and their corresponding protein expressions in porcine longissimus muscle (LM) during postnatal growth of pigs. Five DLY (Duroc×Landrace×Yorkshire) crossbred pigs were selected, slaughtered and sampled at postnatal 7, 30, 60, 120, and 180 days, respectively. Each muscle was subjected to quantity MyHCs protein contents through an indirect enzyme-linked immunosorbent assay (ELISA), to quantity myosin heavy-chains (MyHCs) mRNA abundances using real-time polymerase chain reaction. We calculated the proportion (%) of each MyHC to total of four MyHC for two levels, respectively. Moreover, the activities of several key energy metabolism enzymes were determined in LM. The result showed that mRNA transcription and protein expression of MyHC I, IIa, IIx and IIb in LM all presented some obvious changes with postnatal aging of pigs, especially at the early stage after birth, and their mRNA transcriptions were easy to be influenced than their protein expressions. The relative proportion of each MyHC mRNA was significantly positively related to that of its corresponding protein (p<0.01), and MyHC I mRNA proportion was positively correlated with creatine kinase (CK), succinate dehydrogenase (SDH), malate dehydrogenase (MDH) activities (p<0.05). These data suggested that MyHC mRNA transcription can be used to reflect MyHC expression, metabolism property and adaptive plasticity of porcine skeletal muscles, and MyHC mRNA composition could be a molecular index reflecting muscle fiber type characteristics.

MyoD promotes porcine PPARγ gene expression through an E-box and a MyoD-binding site in the PPARγ promoter region

Peroxisome proliferator-activated receptor γ (PPARγ) is a key transcription factor in adipogenesis and can be regulated by adipogenesis-related factors. However, little information is available regarding its regulation by myogenic factors. In this study, we found that over-expression of MyoD enhanced porcine adipocyte differentiation and up-regulated PPARγ expression, whereas small interfering RNA against MyoD significantly attenuated porcine adipocyte differentiation and inhibited PPARγ expression. The MyoD-binding sites in the PPARγ promoter region at -412 to -396 and -155 to -150 were identified by promoter deletion analysis and site-directed mutagenesis. Electrophoretic mobility shift assays and chromatin immunoprecipitation further showed that these two regions are MyoD-binding sites, both in vitro and in vivo, indicating that MyoD directly interacts with the porcine PPARγ promoter. Thus, our results demonstrate that an Enhancer box and a binding site for a cooperative co-activator of MyoD are present in the promoter region of porcine PPARγ; furthermore, MyoD up-regulates PPARγ expression and promotes porcine adipocyte differentiation.

Abstract P4-03-04: Dynamic tomographic optical breast imaging (TOBI) for neoadjuvant chemotherapy monitoring

Background: Dynamic Diffuse optical imaging using near-infrared light was shown to be promising method for neoadjuvant therapy monitoring as an alternative functional imaging that is low-cost, non-invasive, portable, safe and simple to operate. While optical breast imaging methods rely on "static" assessments of tissue oxy- and deoxy- hemoglobin concentration without contrast agents, they are insufficient for clinical applications. Dynamic tomographic optical imaging induces tumor-sensitive hemodynamic variations, as a contrast mechanism, driven by fractional mammographic compression. These tumor contrast measurements are governed by interlay of tissue biomechanics and oxygen metabolism. In this study we seek to evaluate the predictive value of these biomarkers with respect to treatment outcome.

Methods: A group of 22 patients with locally advanced breast cancer were scanned using our dynamic TOBI system before and during neoadjuvant chemotherapy. In this analysis we focused on pre-treatment, day 7 and day 30 post-treatment dynamic TOBI scans. Both breasts are compressed in turn to 4-8 lbs of force (depending on size) and optical images are acquired every 2 seconds over 2 minutes. We calculate the time course of oxy (HbO), deoxy (HbR)and total (HbT) hemoglobin concentration as well as the hemoglobin oxygen saturation (SO2). Regions of interest are defined in the optical images to correspond to the radiology identified tumor location, and the healthy tissue in the same breast, respectively. We compare the time courses in the two regions at baseline, day 7 and 30 days after initiation of treatment.

Results: In this analysis we present results from 10 patients including 6 responders (defined as greater than 50% reduction in the largest tumor axis from baseline imaging and final pathology) and 4 non-responders. As the compression plates are held in place the tissue collagen matrix begins to stretch, effectively reducing the compression force. At baseline, all patients exhibit a decrease followed by delayed recovery in HbT, and SO2 in the tumor area, in contrast to immediate recovery in surrounding tissue. At day 7 and 30, this contrast is maintained in non-responders (&lt;50% reduction in tumor maximum diameter); however, in responders, the contrast starts decreasing at day 7 and substantially disappears at day 30. Average changes in HbT and SO2, show that the contrast between normal and tumor increases somewhat at day 7 and more noticeably at day 30 in non-responders to NACT. Comparing hemodynamic changes in responders and non-responders, it is clear that at three selected time points (30, 60 and 90 s) during the scan, the contrast between tumor and normal tissue in both ΔHbT and ΔSO2 is reduced for the responders at day 7 and day 30.

Conclusions: These initial results suggest that dynamic optical breast imaging can detect changes due to treatment and have predictive value for the treatment outcome. DTOBI can show the difference in hemodynamic response to compression between tumor and normal tissue and demonstrates the feasibility of using dynamic optical breast tomography for neoadjuvant chemotherapy monitoring. ongoing.

Citation Format: Sajjadi AY, Singh B, Deng B, Boas DA, Moy B, Schapira L, Bardia A, Specht MC, Carp SA, Isakoff SJ. Dynamic tomographic optical breast imaging (TOBI) for neoadjuvant chemotherapy monitoring. [abstract]. In: Proceedings of the Thirty-Eighth Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2015 Dec 8-12; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2016;76(4 Suppl):Abstract nr P4-03-04.

Transcription factor C/EBPβ promotes the transcription of the porcine GPR120 gene

G protein-coupled receptor 120 (GPR120), an adipogenic receptor critical for the differentiation and maturation of adipocytes, plays an important role in controlling obesity in both humans and rodents and, thus, is an attractive target of obesity treatment studies. However, the mechanisms that regulate the expression of porcine GPR120 remain unclear. In this study, electrophoretic mobility shift assay (EMSA) and chromatin immunoprecipitation (ChIP) techniques were used to analyze and identify the binding of C/EBPβ (transcription factor CCAAT/enhancer binding protein beta) to the GPR120 promoter. C/EBPβ overexpression and RNA interference studies showed that C/EBPβ regulated GPR120 promoter activity and endogenous GPR120 expression. The binding site of C/EBPβ in the GPR120 promoter region from -101 to -87 was identified by promoter deletion analysis and site-directed mutagenesis. Overexpression of C/EBPβ increased endogenous GPR120 expression in pig kidney cells (PK). Furthermore, when endogenous C/EBPβ was knocked down, GPR120 mRNA and protein levels were decreased. The stimulatory effect of C/EBPβ on GPR120 transcription and its ability to bind the transcription factor-binding site were confirmed by luciferase, ChIP, and EMSA. Moreover, the mRNA and protein expression levels of C/EBPβ were induced by high fat diet feeding. Taken together, it can be concluded that C/EBPβ plays a vital role in regulating GPR120 transcription and suggests HFD-feeding induces GPR120 transcription by influencing C/EBPβ expression.

Expression profiles of MMP-1 and TIMP-1 in lumbar intervertebral disc degeneration

Lumbar intervertebral disc degeneration (IDD) is a common clinical pathology and has become a focus for research in recent years. Matrix metalloproteinases (MMPs) are enzymes responsible for the degradation of almost all extracellular matrix proteins (ECM). The over-expression of MMPs or tissue inhibitors of metalloproteinases (TIMPs) may disrupt the dynamic balance of the ECM. Therefore, in the current study, the expression levels of MMP-1 and TIMP-1 in lumbar IDD patients were evaluated in an attempt to elucidate their role in IDD pathogenesis and progression. In total, 60 IDD patients were recruited as the experimental group, along with 20 cases of lumbar vertebral injury without disc degeneration as the control group. Preoperative venous blood samples were collected, and intervertebral disc tissues were collected from the lesion during surgery. Serum and tissue levels of MMP-1 and TIMP-1 were quantified by enzyme-linked immunosorbent assay and immunohistochemical staining, respectively. Serum and tissue MMP-1 levels in IDD patients were significantly higher than those in the control group (P < 0.05). Additionally, sub-group analysis revealed that severe IDD patients had higher MMP-1 levels compared with mild or moderate IDD patients (P < 0.05). However, there were no significant differences in TIMP- 1 levels in either the serum or tissues of IDD patients compared to patients in the control group (P > 0.05). These results demonstrate that MMP-1 expression is increased in IDD, with higher expression observed in more severe cases, whereas TIMP-1 expression was similarly expressed in both normal and degenerated discs.

Identification of genes and pathways related to lipopolysaccharide signaling in duckling spleens

Lipopolysaccharide (LPS), the major component of the outer cell wall of Gram-negative bacteria, activates the immune system and threatens the health of livestock and poultry. However, little is known about the genes and pathways involved in the immune response of ducklings to LPS. To elucidate the genes involved in the response of 7-day-old duckling spleens treated with LPS, RNA from LPS-treated and control duckling spleens was analyzed by RNA-Seq. The results showed 11,095 and 10,840 genes with >10 clean reads in the LPS-treated and control groups, respectively. Among these genes, 89 were differentially expressed (log2 ratio ≥ 1, P ≤ 0.01, false discovery rate ≤ 0.001); 67 of these were upregulated and 22 were downregulated in the LPS-treated group compared to the control. GO and GO-rich analysis showed that differentially expressed genes were enriched in 13 functional categories (P < 0.05). Pathway analysis and pathway richness analysis showed that differentially expressed genes were enriched in six pathway categories (P < 0.05). Further analysis showed that some immune system-related signaling pathways, such as the hematopoietic cell lineage, Toll-like receptor signaling pathway, T cell receptor signaling pathway, T cell receptor signaling pathway, complement and coagulation cascades, antigen processing and presentation, and chemokine signaling pathway, are active during the immune response. To confirm the RNA-Seq results, we detected CCL4, LBP, CD71, and STEAP3 expression using real-time PCR analysis, and the results were consistent with the RNA-Seq results. Our results provide new information on the genes involved in the immune response of duckling spleens to LPS.

Study of PIK3CA, BRAF, and KRAS mutations in breast carcinomas among Chinese women in Qinghai

Phosphatidylinositol-3-OH kinase and RAS-activated signaling pathways play an important role in tumor formation. Abnormalities in relevant genes play essential roles in the occurrence and development of many human cancers. Studies of breast cancer have mainly focused on the women in western countries, but few studies have examined the frequency of mutations in PIK3CA, BRAF, and KRAS in Chinese breast cancer patients. In this study, we conducted sequence analysis of PIK3CA, BRAF, and KRAS and determined relationships with the occurrence of breast cancer in women from Qinghai. DNA was extracted from 25 cases of human breast cancer tissue samples. PIK3CA, BRAF, and KRAS mutation analysis was performed by polymerase chain reaction and DNA sequencing. No mutations were found in PIK3CA, BRAF, and KRAS of adjacent tissues. However, PIK3CA mutations were observed in 32% (8) of the 25 breast cancer tissues examined, in which exon 9 accounted for 4% (1), exon 20 accounted for 28% (7), and no mutations were found in exon 1 of PIK3CA. Sequencing of exon 2 of KRAS suggested that 20% (5) of the 25 samples harbored a mutation and 16% (4) of BRAF harbored a mutation. Any mutation in these 3 oncogenes may induce the occurrence and development of breast cancer.

Influence of the image levels of distal femur on the measurement of tibial tubercle-trochlear groove distance--a comparative study

BACKGROUND

The purpose of the present study was to determine whether the image levels of the distal femur affected the measurement of the tibial tubercle-trochlear groove (TT-TG) distance.

METHODS

Thirty sets of computer tomography (CT) images and 30 sets of MR images of the knee were evaluated. The TT-TG distance was quantified at multiple image levels in 1.5-mm increments, covering the proximodistal range of the trochlear groove. The CT measurement was based on osseous landmarks; the magnetic resonance imaging (MRI) measurement was based on cartilaginous and osseous landmarks.

RESULTS

The average TT-TG distances measured with CT, with MRI based on cartilaginous landmarks, and with MRI based on osseous landmarks were 15.74 mm (SD 3.83 mm), 12.8 mm (SD 5.67 mm), and 12.36 mm (SD 5.58 mm), respectively. No significant difference was found across image levels in the CT measurement and the MRI measurement upon osseous landmarks (P = 0.64, P = 0.11); yet, the difference was significant in the MRI measurement upon cartilaginous landmarks (P < 0.01). Large deviation was found between levels in individual subjects in all the three sorts of measurement. The proximal levels were the most variable, while the mid levels were the least variable.

CONCLUSIONS

Measurements of the TT-TG distance are not identical across the levels of the distal femur. Cautions should be taken when specific image slices were selected for evaluation.

[Treatment of Chronic Heart Failure with Carotid Plaque Patients by Yiqi Huoxue Tongyang Xezhuo Recipe]

OBJECTIVE

To evaluate the clinical effectiveness of Yiqi Huoxue Tongyang Xiezhuo Recipe (YHTXR, capable of supplementing qi, activating blood, warming yang, and discharge turbidity) in treating coronary atherosclerotic heart disease (CAHD). and chronic heart failure (CHF) with carotid plaque patients, and to explore new ways of Chinese medicine (CM).

METHODS

Totally 69 CAHD-CHF patients of qi deficiency phlegm stasis syndrome (QDPSS) with carotid plaque were recruited in this study using parallel cohort method. They were assigned to the treatment group (35 cases) and the control group (34 cases). Patients in the control group received routine treatment of Western medicine, while those in the treatment group were additionally treated with YHTXR (twice daily). The therapeutic course for all was three months. Cardiac function levels, echocardiography, carotid plaque, blood lipids and safety indicators were observed before and after treatment.

RESULTS

After treatment the improvement of cardiac function levels was better in the treatment group than in the control group (P < 0.05). Decreased LDL-C levels were higher in the treatment group than in the control group (P < 0.01). There was statistical difference in left ventricular ejection fraction (LVEF), carotid intima-media thickness (IMT), LDL-C, TC, TG in the treatment group between before and after treatment (P < 0.05). LDL-C and TG also decreased in the control group after treatment (P <0.05). There was no significant difference in the left ventricular ejection fraction, carotid IMT, or TC in the control group between before and after treatment (P > 0.05). There was no significant difference in stroke volume, left ventricular end-diastolic diameter, the area of carotid artery plaque, or HDL-C in the two groups between before and after treatment (P > 0.05).

CONCLUSIONS

YHTXR could effectively improve cardiac functions of CAHD-CHF patients of QDPSS with carotid plaque, reduce blood lipids and IMT. It had no significant adverse reactions for elderly patients in short term.

Roll-to-Roll Green Transfer of CVD Graphene onto Plastic for a Transparent and Flexible Triboelectric Nanogenerator

A novel roll-to-roll, etching-free, clean transfer of CVD-grown graphene from copper to plastic using surface-energy-assisted delamination in hot deionized water is reported. The delamination process is realized by water penetration between the hydrophobic graphene and a hydrophilic native oxide layer on a copper foil.The transferred graphene on plastic is used as a high-output flexible and transparent triboelectric nanogenerator.

Reduction-sensitive polymeric nanocarriers in cancer therapy: a comprehensive review

Redox potential is regarded as a significant signal to distinguish between the extra-cellular and intra-cellular environments, as well as between tumor and normal tissues. Taking advantage of this physiological differentiation, various reduction-sensitive polymeric nanocarriers (RSPNs) have been designed and explored to demonstrate excellent stability during blood circulation but rapidly degrade and effectively trigger drug release in tumor cells. Therefore, this smart RSPN delivery system has attracted much attention in recent years, as it represents one of the most promising drug delivery strategies in cancer therapy. In this review, we will provide a comprehensive overview of RSPNs with various reducible linkages and functional groups up to date, including their design and synthetic strategies, preparation methods, drug release behavior, and their in vitro and in vivo efficacy in cancer therapy. In addition, dual- and triple-sensitive nanocarriers based on reducible disulfide bond-containing linkages will also be discussed.

2D Hybrid Nanostructured Dirac Materials for Broadband Transparent Electrodes

Broadband transparent electrodes based on 2D hybrid nanostructured Dirac materials between Bi2 Se3 and graphene are synthesized using a chemical vapor deposition (CVD) method. Bi2 Se3 nanoplates are preferentially grown along graphene grain boundaries as "smart" conductive patches to bridge the graphene boundary. These hybrid films increase by one- to threefold in conductivity while remaining highly transparent over broadband wavelength. They also display outstanding chemical stability and mechanical flexibility.

Roll-to-Roll Encapsulation of Metal Nanowires between Graphene and Plastic Substrate for High-Performance Flexible Transparent Electrodes

Transparent conductive film on plastic substrate is a critical component in low-cost, flexible, and lightweight optoelectronics. Industrial-scale manufacturing of high-performance transparent conductive flexible plastic is needed to enable wide-ranging applications. Here, we demonstrate a continuous roll-to-roll (R2R) production of transparent conductive flexible plastic based on a metal nanowire network fully encapsulated between graphene monolayer and plastic substrate. Large-area graphene film grown on Cu foil via a R2R chemical vapor deposition process was hot-laminated onto nanowires precoated EVA/PET film, followed by a R2R electrochemical delamination that preserves the Cu foil for reuse. The encapsulated structure minimized the resistance of both wire-to-wire junctions and graphene grain boundaries and strengthened adhesion of nanowires and graphene to plastic substrate, resulting in superior optoelectronic properties (sheet resistance of ∼8 Ω sq(-1) at 94% transmittance), remarkable corrosion resistance, and excellent mechanical flexibility. With these advantages, long-cycle life flexible electrochromic devices are demonstrated, showing up to 10000 cycles.

GSK3β negatively regulates LPS-induced osteopontin expression via inhibiting its transcription

Osteopontin (OPN) is expressed by a variety of immune cells and is critical for both innate and adaptive immune responses. The expression status of OPN might be tightly regulated to maintain immune homeostasis. However, the mechanisms by which OPN is negatively regulated in LPS-stimulated macrophages remain largely unknown. In this study, we showed that glycogen synthase kinase 3β (GSK3β) inhibitors - SB216763, LiCl and azakenpaullone - enhanced LPS-induced OPN expression in mouse peritoneal macrophages. GSK3β knock-down had the similar effects. Furthermore, we found that GSK3β inhibitors and GSK3β knock-down both increased the activity of OPN promoter in LPS-stimulated macrophages. GSK3β inhibitor-mediated enhancement of LPS-induced OPN promoter activity was abrogated in GSK3β siRNA-treated macrophages. Therefore, we identified GSK3β as a negative regulator of OPN expression and suggest GSK3β as a potential therapeutic target for the intervention of diseases with uncontrolled OPN production.

[Nutrient Exchange Between Meixi River and Yangtze River Due to the Typical Interaction Process of the Three Gorges Reservoir and Its Tributary]

Frequent algal blooms have been observed in the Meixi bay of the Three Gorges Reservoirs (TGR) since its initial filling. In order to understand the effects of intrusions from Changjiang mainstream on the nutrient supply of the Meixi Bay, a detailed field monitoring was conducted from August 2012 to July 2013. The results showed that there were significant intrusions from the mainstream to the Meixi Bay during the different water level scheduling periods of the TGR. As a result, the invading flow from the mainstream of the Changjiang caused a significant effect on the nutrient distribution in the Meixi River. Annually, the mainstream transportednet fluxes of 5 478.02 t DIN, 234.04 t DIP and 5 935.22 t DSi to the Meixi Bay, which were 2.37 times, 4.32 times and 1.33 times of the corresponding fluxes from the upstream, respectively. The influence on the nutrient distributions was not only limited in the estuary area but also in the upper reaches, the supply of DIP changed the nutrient structure and relieved the P restrictions on phytoplankton growth.

Health-related quality of life of the rural-China left-behind children or adolescents and influential factors: a cross-sectional study

BACKGROUND

Due to sustained export of labor service, the left-behind children/ adolescents in rural areas of China have become a group that can no longer be neglected. However, even up to this day, little is known about the health-related quality of life (HRQoL) of the left-behind children/adolescents, particularly in Midwest China. This study aims at investigating their living condition and analyzing the influential factors of their HRQoL.

METHODS

A cross-sectional study based on households was conducted and 1363 children or adolescents from rural areas of 6 provinces in China, among whom 608 were left-behind and 755 were non-left-behind, were enrolled in a multistage sampling. HRQoL was revealed using the Pediatric Quality of Life Inventory (PedsQL). Differences in scores were analyzed using rank sum tests, and multivariate analyses were conducted with multiple linear regression.

RESULTS

There was a total of 608 (44.61%) left-behind children or adolescents, and they scored significantly lower in terms of the HRQoL synthesis scores (F = 6.14, P < 0.05), Physical Functioning (H = 33.18, P < 0.05), Emotional Functioning (H = 24.99, P < 0.05) and Social Functioning (H = 12.24, P < 0.05), compared with the non-left-behind. Multiple linear regressions indicated that age and mother's final academic qualification were in positive correlation with the HRQoL of the left-behind children, while mother's longer migrant working time and less frequent visits, and being reared by uncle/aunt etc., were potential risk factors for the left-behind children.

CONCLUSIONS

The HRQoL scores of left-behind children or adolescents were significantly lower than those of their counterparts both in the physical and the psychological domains. Influential factors should be considered when relevant policies are being made and intervening practices are being undertaken in the future, so as to improve the HRQoL of the left-behind children or adolescents.

PPARγ and MyoD are differentially regulated by myostatin in adipose-derived stem cells and muscle satellite cells

Myostatin (MSTN) is a secreted protein belonging to the transforming growth factor-β (TGF-β) family that is primarily expressed in skeletal muscle and also functions in adipocyte maturation. Studies have shown that MSTN can inhibit adipogenesis in muscle satellite cells (MSCs) but not in adipose-derived stem cells (ADSCs). However, the mechanism by which MSTN differently regulates adipogenesis in these two cell types remains unknown. Peroxisome proliferator-activated receptor-γ (PPARγ) and myogenic differentiation factor (MyoD) are two key transcription factors in fat and muscle cell development that influence adipogenesis. To investigate whether MSTN differentially regulates PPARγ and MyoD, we analyzed PPARγ and MyoD expression by assessing mRNA, protein and methylation levels in ADSCs and MSCs after treatment with 100 ng/mL MSTN for 0, 24, and 48 h. PPARγ mRNA levels were downregulated after 24 h and upregulated after 48 h of treatment in ADSCs, whereas in MSCs, PPARγ levels were downregulated at both time points. MyoD expression was significantly increased in ADSCs and decreased in MSCs. PPARγ and MyoD protein levels were upregulated in ADSCs and downregulated in MSCs. The CpG methylation levels of the PPARγ and MyoD promoters were decreased in ADSCs and increased in MSCs. Therefore, this study demonstrated that the different regulatory adipogenic roles of MSTN in ADSCs and MSCs act by differentially regulating PPARγ and MyoD expression.

A microfluidic device enabling high-efficiency single cell trapping

Single cell trapping increasingly serves as a key manipulation technique in single cell analysis for many cutting-edge cell studies. Due to their inherent advantages, microfluidic devices have been widely used to enable single cell immobilization. To further improve the single cell trapping efficiency, this paper reports on a passive hydrodynamic microfluidic device based on the "least flow resistance path" principle with geometry optimized in line with corresponding cell types. Different from serpentine structure, the core trapping structure of the micro-device consists of a series of concatenated T and inverse T junction pairs which function as bypassing channels and trapping constrictions. This new device enhances the single cell trapping efficiency from three aspects: (1) there is no need to deploy very long or complicated channels to adjust flow resistance, thus saving space for each trapping unit; (2) the trapping works in a "deterministic" manner, thus saving a great deal of cell samples; and (3) the compact configuration allows shorter flowing path of cells in multiple channels, thus increasing the speed and throughput of cell trapping. The mathematical model of the design was proposed and optimization of associated key geometric parameters was conducted based on computational fluid dynamics (CFD) simulation. As a proof demonstration, two types of PDMS microfluidic devices were fabricated to trap HeLa and HEK-293T cells with relatively significant differences in cell sizes. Experimental results showed 100% cell trapping and 90% single cell trapping over 4 × 100 trap sites for these two cell types, respectively. The space saving is estimated to be 2-fold and the cell trapping speed enhancement to be 3-fold compared to previously reported devices. This device can be used for trapping various types of cells and expanded to trap cells in the order of tens of thousands on 1-cm(2) scale area, as a promising tool to pattern large-scale single cells on specific substrates and facilitate on-chip cellular assay at the single cell level.

Fluorescent labeling for clonal selection of Marc 145 cells secreting high levels of recombinant protein PBD-1

Despite the powerful impact gene expression markers like the green fluorescent protein (GFP) or enhanced GFP (EGFP) exert on linking the expression of recombinant protein for selection of high producers in recent years, there is still a strong incentive to develop more economical and efficient methods for isolating mammalian cell clones secreting high levels of recombinant proteins. Here we present a new method based on the co-expression of EGFP that allows clonal selection in standard 96-well cell culture plates. The genes encoding the EGFP protein and the related protein are linked by an internal ribosome entry site and thus are transcribed into the same mRNA in an independent translation process. Since both proteins arise from a common mRNA, the EGFP expression level correlates with the expression level of the therapeutic protein in each clone. By expressing recombinant porcine β-defensin 1 in Marc 145 cells, we demonstrate the robustness and performance of this technique. The method can be served as an alternative to identify high-producer clones with various cell sorting methods.

The cell envelope proteome of Aggregatibacter actinomycetemcomitans

The cell envelope of gram-negative bacteria serves a critical role in maintenance of cellular homeostasis, resistance to external stress, and host-pathogen interactions. Envelope protein composition is influenced by the physiological and environmental demands placed on the bacterium. In this study, we report a comprehensive compilation of cell envelope proteins from the periodontal and systemic pathogen Aggregatibacter actinomycetemcomitans VT1169, an afimbriated serotype b strain. The urea-extracted membrane proteins were identified by mass spectrometry-based shotgun proteomics. The membrane proteome, isolated from actively growing bacteria under normal laboratory conditions, included 648 proteins representing 27% of the predicted open reading frames in the genome. Bioinformatic analyses were used to annotate and predict the cellular location and function of the proteins. Surface adhesins, porins, lipoproteins, numerous influx and efflux pumps, multiple sugar, amino acid and iron transporters, and components of the type I, II and V secretion systems were identified. Periplasmic space and cytoplasmic proteins with chaperone function were also identified. A total of 107 proteins with unknown function were associated with the cell envelope. Orthologs of a subset of these uncharacterized proteins are present in other bacterial genomes, whereas others are found exclusively in A. actinomycetemcomitans. This knowledge will contribute to elucidating the role of cell envelope proteins in bacterial growth and survival in the oral cavity.

Restoration of miR-101 suppresses lung tumorigenesis through inhibition of DNMT3a-dependent DNA methylation

The deregulation of miR-101 and DNMT3a has been implicated in the pathogenesis of multiple tumor types, but whether and how miR-101 silencing and DNMT3a overexpression contribute to lung tumorigenesis remain elusive. Here we show that miR-101 downregulation associates with DNMT3a overexpression in lung cancer cell lines and patient tissues. Ectopic miR-101 expression remarkably abrogated the DNMT3a 3′-UTR luciferase activity corresponding to the miR-101 binding site and caused an attenuated expression of endogenous DNMT3a, which led to a reduction of global DNA methylation and the re-expression of tumor suppressor CDH1 via its promoter DNA hypomethylation. Functionally, restoration of miR-101 expression suppressed lung cancer cell clonability and migration, which recapitulated the DNMT3a knockdown effects. Interestingly, miR-101 synergized with decitabine to downregulate DNMT3a and to reduce DNA methylation. Importantly, ectopic miR-101 expression was sufficient to trigger in vivo lung tumor regression and the blockage of metastasis. Consistent with these phenotypes, examination of xenograft tumors disclosed an increase of miR-101, a decrease of DNMT3a and the subsequent DNA demethylation. These findings support that the loss or suppression of miR-101 function accelerates lung tumorigenesis through DNMT3a-dependent DNA methylation, and suggest that miR-101-DNMT3a axis may have therapeutic value in treating refractory lung cancer.